Properties of Different Pumice Grades Blended with Cement

Abstract

The research focused on determining the effect of fresh and hardened properties of paste, mortar, and concrete using high Si-Al-Na–containing pumice as a supplementary cementitious material. Three crushed and sieved powder grades of this pumice were investigated at different percentages of cement replacement, up to 30%. Of the fresh properties, hydration kinetics from a calorimeter showed lower heat of hydration, and Vicat setting times indicated slower hardening response with the increased addition of pumice of the same grade. The finer grades of pumice showed reduced compressive strength compared to the control mixture, but enhanced strength compared to coarser grades. Durability tests of mortar samples were also performed. The addition of pumice and the finer grades of pumice showed enhanced resistance against both sulfate attack and alkali–silica reaction. A replacement of cement by 15% regardless of coarseness of the pumice grade was sufficient to prevent alkali–silica reaction.